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# Licensed under the Apache License, Version 2.0 (the "License");
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#     http://www.apache.org/licenses/LICENSE-2.0
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import torch
from torch import Tensor


class PrecipNorm:
    """Precipitation normalization following Pathak et al. (2022)"""

    def __init__(
        self,
        epsilon=1e-5,
    ):
        self.epsilon = epsilon

    @torch.no_grad()
    @torch.compile
    def normalize(self, tp: Tensor) -> Tensor:
        return torch.log1p(tp / self.epsilon)

    @torch.no_grad()
    @torch.compile
    def denormalize(self, x: Tensor) -> Tensor:
        return torch.expm1(x) * self.epsilon
